DESCRIPTION: (Applicant's Description) In this application, we propose to develop rapid and efficient methods to prepare purified populations of neoplastic epithelial cells for evaluation by new DNA and RNA array-based molecular detection technologies. Recent developments in high speed/high volume nucleic acid sequencing and hybridization arrays have enabled the analysis of human tissue specimens on an unprecedented scale. However, accuracy in nucleic acid sequencing, detection of loss of heterozygosity (LOH) and measurement of patterns of gene expression require that the cellular material submitted for molecular analysis be as free as possible from contaminating nontumor cells. While one approach may be to microdissect the desired cells, this method is laborious, not easily automated, yields small cell numbers, and is not always possible. We propose to optimize a combination of cell preparation and flow cytometric cell sorting technologies to address the need to rapidly isolate cells of interest in larger numbers. We will apply these methods and validate the results using array-based analysis of loss of heterozygosity, DNA sequencing and RNA expression hybridization.